The gear I currently use for my "street-people photography" is a Nikon F3HP (with MD-4 motordrive), and either a Nikkor 105mm f/2.5, or a Nikkor ED 180mm f/2.8 lens. I also have a nice Tokina AT-X 28-85mm f/2.8-4 lens for when I need to go wide.

Photographing total strangers as they go about their business can be hard at first, but once you gain confidence in yourself, and your equipment, it gets easier. Make your shots quick, and be unobtrusive as you can...Even IF using a camera/motordrive combo that's as large and as "noisy" as the F3HP/MD-4 is.